Consolidated natural silk and process of making the same.



PETER SGl-IMID, ()l" BASEL, SWITZERLAND.

CGNSOLIDATED NATURAL SILK AND PROCESS OF MAKING THE SAME.

Application filed December 11, 1906.

Specification of Letters Patent.

Patented Aug. 25, 1908.

Serial No. 347,334.

To all whom it may concern:

Be it known that 1, PETER, Serrano, a citi- -Zen of the Swiss Republic, and resident of Basel, Switzerland, have invented a new Consolidated Natural Silk and a Process of Making the Same, of which the following is a full and exact specification.

It is known that natural-raw silk can be consolidated by hardening its coating of sericin, which. envelops the fibroin; by means of formaldehyde (see for example the United States Letters Patent No. 549257 dated November 5th, 1895). This treatment of the raw silk with formaldehyde had however not the desired results, since the thereby obtained consolidated silkv was not sufficiently supple and remained dull at the dyeing. I succeeded in avoiding these disadvantages by freeing the natural silk with sericin hardened by formaldehyde from the exterior or superficial layers or strata of sericin, which are precisely the most spongy and prevent the obtaining of bright, glossy tints in dyeing, the hardened sericin enveloping the libroin becoming thus thinner and consequently the fiber remaining suppler.

For carrying out my invention, 1 proceed for example as follows: The raw natural silk in. the form of threads or in woven, knitted, plaited, etc. condition, or in the form of silk waste, is placed in a formahlohyde solution containing 2 to 5 per cent pure formaldehyde of the weight of the treated silk material and is allowed to remain in this solution for about 1 to 3 days at ordinary temperature, in order to harden entirely the sericin, what occurs when the scricin coating of the raw silk has become insoluble in water. The raw silk thus treated is thencventually after it has been dried -subjecteil. to the action ol the Soap latherproduccd by l'ieating soap water to boiling in the presence of air (for example as it is specified in my United. States Letters Patent Ser. No 848605 dated March 26, 1907), during few minutes to 45 minutes or more, according to the nature of the silk or the more or less energetic action of the for-- maldehyde or according as the hardened scricin coating shall be softened or made soluble more or less deeply. T his treatment with. soap lather is stopped. when a sample of the treated raw silk loses by its washing 3. to 5 per cent of the original weight of fibroin less than when the same-silk is'entirely ungumnicd by the usual process. Finally the silk is washed in water, whereby the softened exterior layers of the seririn coating are removed from tho libroin, while the inner,

more dense layers of the said hardened scricin coating, which have not been made solu blo by the soap lather, remain on the libroin. The silk thus obtained has a hardened sericin coating of more or less reduced thickness, but in every case freed from the superficial or exterior layers of the sericin coating shown by the said silk before treatment. The sericin remaining on the obtained silk is condensed to a silky matter analogous to the fibroin and assuming as this latter a bright glossy appearance on dyeing. The said sericin increases the volume of the silk thread. The silk having a reduced sericin coating hardened by formaldehyde has further a greater allinity for the weighting substances usually employed, so that it can be weighted n1ore.-

. By dyeing the silk having a reduced seri-' cin coating hardened by formaldehyde, the said hardened sericin protects the lihroin, so thatthe physical structure of the silk is saved and the dyed silk becomes less lowny.

The silk treated by the new process is designed to be substituted for the ungununcd silk usually employed,

What I claim is:

1. The herein described process for the manufacture of a consolidated natural silk consisting in. first treating the raw natural silk with a formaldehyde solution in order to harden its sericin coating, then making soap water and treating the raw silk having a hardened coating with lather ol' the said soap water in order to soften the exterior laycrs ol' the said seririn coating and finally washing the silk thus treated in order to remove the said softened exterior layers of soricin.

2. As a new article ofnmnulacturc the described consolidatcd natural silk from which only the exterior layers of scririn have been removed while its libroin remains covered by the inner, more dense sericiu layers hardened by hwmaldehyde, and representing about 3 to 5 per cent oi the Weight of the said fibroin, the said silk being sullicicntly supple to be substituted for the silk entirely unmy name thi gurnrned, assuming, on dyeing, the glossy the presence of two subscribing Witnesses. appearance of this latter becoming by dye- .ing less downy than the entirely un urnmed PETER SCHMID 5 silk and having a greater affinity t an this Witnesses:

latter for weighting substances. GEO. GIFFORD, In witness whereof I have hereunto signed AMAND BITTER,

s 30th day of November 1906, in 

